Summary AQA A-Level Psychology Paper 1 Revision Notes -Biopsychology

Biopsychology Revision Notes:
Nervous System & Endocrine System
 Nervous System: Main internal communication system, responds to stimuli, coordinates
body organs.
o Central Nervous System (CNS): Brain and spinal cord, manages complex
commands.
o Peripheral Nervous System (PNS): Transmits messages to/from CNS via neurons.

 Autonomic Nervous System (ANS): Regulates involuntary functions (e.g.,
heart rate, stress response).
 Somatic Nervous System (SNS): Controls muscle movement.
 Endocrine System: Glands release hormones (e.g., thyroid releases thyroxine) affecting
organs.
 Hypothalamus
o Location: In the brain

o Function: Regulates body functions by receiving information from various sources;
controls the pituitary gland
o Hormone: Corticotropin-releasing hormone (CRH) – regulates the HPA axis,
important for long-term stress response
 Pituitary Gland
o Location: In the brain

o Function: Known as the "master gland," controls hormone release from other
endocrine glands
o Hormones:

 Releasing hormones – target cells in specific glands to trigger hormone
release
 ACTH (Adrenocorticotropic hormone) – stimulates cortisol production in
response to stress
 Luteinising hormone (LH) – regulates sex hormone release (e.g., testosterone
in males, oestrogen in females)
 Adrenal Gland
o Location: Above the kidneys

o Function: Prepares body for emergency ("fight or flight" response)

o Structure:

 Adrenal Cortex: Releases cortisol – supports cardiovascular functions and
stress response

,  Adrenal Medulla: Releases adrenaline and noradrenaline – increases heart
rate, blood pressure, and energy availability for stress response
 Pineal Gland
o Location: In the brain

o Function: Regulates the sleep-wake cycle (circadian rhythm)

o Hormone: Melatonin – released in response to darkness, promoting sleep

 Testes
o Location: Groin area (only in males)

o Function: Involved in male puberty, sperm production, and testosterone release

o Hormone: Testosterone – supports male development (muscle growth, deepened
voice, body hair growth)
 Ovaries
o Location: Reproductive system (only in females)

o Function: Produces eggs and releases hormones during the menstrual cycle

o Hormones:

 Oestrogen – aids in ovulation, thickens uterus lining
 Progesterone – maintains the thickened uterus lining
 Fight or Flight Response: ANS and endocrine system collaborate.
o Sympathetic State: Stress perceived → ANS triggers adrenaline release → increased
heart rate, sweating.
o Parasympathetic State: Returns body to normal post-stress.
NERVOUS SYSTEM (NS)
The nervous system consists of the
brain, spinal cord, sensory organs
and nerves.
It is our way of communicating
internally - it processes and
responds to information from the
environment and coordinates
different cells in the body




CENTRAL NERVOUS SYSTEM (CNS)
The central nervous system is made up of PERIPHERAL NERVOUS SYSTEM (PNS)
the brain and the spinal cord. The peripheral nervous system
The brain: centre of all consciousness, transmits messages to and from the
split up into two hemispheres. Humans central nervous system.
have higher mental functions than Autonomic: governs vital functions and
animals is divided into sympathetic and
The spinal cord: is an extension from the parasympathetic
brain, responsible for reflex actions and Somatic: controls muscle movement
passes messages to and from the brain




BRAIN SPINAL CHORD SOMATIC NERVOUS SYSTEM (SNS) AUTONOMIC NERVOUS SYSTEM (ANS)
The brain is the centre of all The spinal cord is an extension Controls muscle movements and It governs the vital functions and is
consciousness and split up into from the brain and makes it receives information from sensory divided into sympathetic and
two hemispheres. The outer responsible for reflex actions. receptors. parasympathetic states.
layer of the brain (cerebral It passes messages to and Sympathetic: carries signals to alert
cortex) is highly developed in from the brain and connects the body of dangers
humans the nerves from to the PNS Parasympathetic: carries signals to
return the body to normal bodily
standards




SYMPATHETIC BRANCH PARASYMPATHETIC BRANCH

It carries signals to alert It carries signals to return the
the body of dangers body to normal bodily
standards

, Neurons & Synaptic Transmission
 Neurons: Nerve cells transmitting messages chemically/electrically.
o Types:

 Motor: CNS to muscles/glands.
 Sensory: PNS to CNS.
 Relay: Connect sensory neurons to motor/relay neurons.
o Structure:

 Soma: Contains genetic material.
 Dendrites: Carry impulses to soma.
 Axon: Carries impulses away from soma.
 Myelin Sheath: Protective layer on axon, speeds transmission.
 Nodes of Ranvier: Gaps in myelin sheath, facilitating faster impulse travel.
 Terminal Buttons: Allow communication with other neurons at synapse.

Features Sensory neuron Relay neuron Motor neuron
Function of Conveys a message along Transfers message to the motor Carries the message to an
neuron
the peripheral nervous neuron from the spinal cord - effector like a muscle which
system to the central connects the sensory and motor caused it to move
nervous system neuron
Length of Long dendrites and short Short dendrites and short axons Short dendrites and long/large
fibres
axon axons (PNS)
Position of In the middle, coming off of In the middle of the axon on the Amongst the dendrites at the
cell body
the side of the axon neuron top of the neuron

Synaptic Transmission
 Messages are transmitted electrically within neurons, chemically between them.
 At the synapse, an impulse in the pre-synaptic neuron releases neurotransmitters from vesicles
into the synapse.
 Neurotransmitters bind to receptors on the post-synaptic neuron, converting the chemical
signal back to an electrical impulse.
 Excess neurotransmitters are reabsorbed by the pre-synaptic neuron (reuptake).
 Transmission across neurons forms a neural network.
 Each neurotransmitter has a unique shape, fitting specific receptors on the post-synaptic cell.
o Excitatory neurotransmitters (e.g., adrenaline) increase the likelihood of impulse
transmission.